1. Field of the Inventions
The present inventions generally relate to an air intake device for an engine, and more particularly to an air intake device that introduces ambient air to an engine.
2. Description of the Related Art
Typically, vehicles such as, for example, automobiles and motorcycles have an engine that powers drive wheels. An air intake device introduces or guides ambient air to the engine. The air intake device can house a cleaner element, also referred to as a filter. Such an air intake device usually has an inlet opening upstream of the filter and an outlet opening downstream of the filter. The outlet opening is coupled with the engine.
During operation, the ambient air enters the intake device through the inlet opening, passes through the filter and goes to the engine through the outlet opening. Negative intake pressure generated in the engine pulls the air through the intake device and the filter. The filter removes foreign substances from the air.
Generally, such an intake device is designed such that an internal air passage defined therein has a relatively large cross-sectional area. This reduces a pressure loss caused by the intake device and thus allows air to flow quickly to the engine. As a result, engine performance, particularly acceleration performance, can be greatly improved.
Conventionally, many different intake devices have been used. For example, Japanese Patent Publication No. P2002 364467A discloses one of such intake devices.
Conventional intake devices, however, are likely to be bulky if a large cross-sectional area is provided therein. Generally, motorcycles have a less space available for the intake device compared to automobiles. This is because the motorcycles typically have a seat which the rider straddles. Usually, the intake device is disposed in front of the seat and in a relatively narrow space in which, for example, the engine and a fuel tank are placed. The engine and the fuel tank are large enough to almost occupy the entire space.